Minnesota Vikings running back Adrian Peterson won his appeal Thursday when Judge David S. Doty granted a petition to vacate the indefinite suspension handed down by NFL commissioner Roger Goodell.

The NFL then appealed the decision and returned Peterson to the commissioner's exempt list.

"There is no dispute that the Commissioner imposed Peterson's discipline under the New Policy," Doty wrote Thursday. "It is also undisputed that in the (Ray) Rice arbitration, the hearing officer unequivocally recognized that the New Policy cannot be applied retroactively, notwithstanding the Commissioner's broad discretion in meting out punishment under the CBA.

"Consistent with that recognition, the Commissioner has acknowledged that he did not have the power to retroactively apply the New Policy: The policy change was forward looking because the League is 'required to provide proper notice.' Yet, just two weeks later, the Commissioner retroactively applied the New Policy to Peterson."

Goodell's decision to indefinitely suspend former Ravens running back Ray Rice was overturned by arbitrator Barbara Jones, a U.S. district judge. The NFL claimed the ruling should be irrelevant to Peterson's case, but Doty said he found "no valid basis to distinguish this case over the Rice matter."

Doty's ruling does not equate to reinstatement for Peterson, whose case returns to the arbitration process. His original appeal was denied by Harold Henderson. In Doty's 16-page ruling Thursday, he said Henderson "disregarded the law of the shop and in doing so failed to meet his duty."

Doty, who heard Peterson's formal appeal Feb. 6, has long been viewed as a player-friendly judge.

"This is a victory for the rule of law, due process and fairness," the NFLPA said in a statement Thursday. "Our collective bargaining agreement has rules for implementation of the personal conduct policy and when those rules are violated, our union always stands up to protect our players' rights. This is yet another example why neutral arbitration is good for our players, good for the owners and good for our game."

The NFL said Thursday through spokesman Brian McCarthy that it would "review the decision." It later announced that it was appealing and placed Peterson back on the exempt list, where he spent most of the 2014 season.

In a written statement, the NFL said: "We believe strongly that Judge Doty's order is incorrect and fundamentally at odds with well-established legal precedent governing the district court's role in reviewing arbitration decisions. As a result, we have filed notice of appeal to have the ruling reviewed by the Eighth Circuit Court of Appeals. In the interim, Adrian Peterson will be returned to the Commissioner Exempt List pending further proceedings by appeals officer Harold Henderson or a determination by the Eighth Circuit Court."

Peterson has three years remaining on his contract. He is owed $12.75 million next season.

It's not clear whether he wants to return to the Vikings. His agent, Ben Dogra, had an altercation with chief contract negotiator Rob Brzenski at the Scouting Combine in Indianapolis last week when Dogra reportedly told the Vikings that Peterson was done in Minneapolis. Reports had surfaced that Peterson was not fully comfortable returning to the team.

Peterson told friends that he felt "betrayed" by the Vikings, according to reports. However, Peterson's father said last week that he would not rule out a return to the team.

Peterson can be traded after the league year begins March 10. Last year, he told Cowboys owner Jerry Jones that he would love to play in Dallas. DeMarco Murray, who led the NFL in rushing last season and was voted Offensive Player of the Year, is an unrestricted free agent.

Vikings general manager Rick Spielman said at the combine that the Vikings would welcome Peterson back. Coach Mike Zimmer said he also valued Peterson as a football player. However, the team is not likely to bring Peterson back at a lofty price tag.

Peterson was placed on the commissioner's exempt list in September, when charges for child abuse were filed in Texas involving Peterson's 4-year-old son.

He had been charged with injuring his 4-year-old son in May, causing visible injuries to his legs, thighs and scrotum. Peterson claimed he did not intend injury while disciplining the boy with a wooden switch.

Peterson avoided jail time pleading no contest to reckless assault on Nov. 4, and Goodell suspended Peterson for the rest of the 2014 season for a violation of the personal conduct policy.

Under guidelines Goodell established, Peterson would not have been eligible for reinstatement until April 15.

Peterson said Feb. 6 he felt like he "got a fair hearing" in Minneapolis, where he presented his argument to Doty. At the time, Peterson said he wanted to stay with the Vikings.